Methods for manufacturing a hollow profile, in particular a tube-type hollow profile, made of fibre-reinforced thermoplastic are described in DE 10 2011 018 419 A1 and in DE 10 2011 018 420 A1. In accordance with these methods, a braid of a plurality of hybrid rovings or fibre tapes, which comprise reinforcing fibres as well as a thermoplastic matrix material, is provided by braiding. In order to achieve impregnation of the fibres and consolidation, the braid is then pulled into a die. The die has several zones which are provided with means for adjusting the temperature. According to the pultrusion methods of DE 10 2011 018 419 A1 and DE 10 2011 018 420 A1, in an impregnation zone of the die, a first one of these means provides for heating up to the melting temperature of the thermoplastic matrix material.
However, methods such as those described in DE 10 2011 018 419 A1 or DE 10 2011 018 420 A1 may lead to considerable friction when the braid is pulled through the die. Therefore, such methods require complex and costly measures, described in these documents, to be taken in order to ensure that the friction is lowered to an acceptable level, so as to avoid, for example, accumulation of fibres upstream of the die during pultrusion, deformation of the braid and damage to the fibres.
Furthermore, the length of fibre-reinforced composite product that can be produced per unit of time, and the speed at which the braid can be pulled through the die for this purpose, is limited by the capability of the manufacturing arrangement employed to effectively heat the braid to the process temperature that is required, in particular the melting temperature of the matrix material. If heating the braid is performed by means of surface contact with a heated die, sufficiently rapid, thorough and uniform heating of the braid is rather difficult to achieve.
Moreover, with regard to industrial applications, it may be desirable to further increase the product quality, for example regarding porosity, fibre damage and alignment, of the composite product that is produced, compared to known methods and arrangements, and/or to decrease the efforts that have to be made in order to satisfy industry standards regarding product quality.